The growing number of food makers who want to label their products “gluten free” have to start following stricter rules starting this week.

Aug. 5 marked the deadline for compliance with the U.S. Food and Drug Administration’s new gluten-free labeling rules, which were approved one year ago.

The rules are designed to make food safer for consumers who have celiac disease and gluten sensitivity. About 3 million Americans have celiac disease and the gluten-free market has ballooned to $20 billion by some estimates.

The new rules require food companies to keep the amount of gluten from all sources to less than 20 parts per million, a standard accepted as safe for those who have celiac disease based on medical research. The rules apply to all packaged food and supplements regulated by the FDA.

For the first time, food makers will have to control any gluten from cross-contamination. Previously, the only requirement for use of a gluten free label was that the ingredients themselves were gluten free.  Food companies now have to be sure the ingredients they use are not cross-contaminated in the field or during transport or processing.  Cross contamination can occur when grains are shipped in shared trucks or milled in shared facilities. It can also occur when products are stored, made or packaged in facilities or on equipment also used for gluten-containing products.

“We’ve been waiting for these rules for a long time,” said Amy Ratner, editor of Gluten-Free Living. “We’ve been following their progress from the very beginning, and we know how important they are for people who have celiac disease or gluten sensitivity.”

Medical research has shown that many people who have celiac disease and carefully follow the gluten-free diet still continue to have symptoms. “The rules will help clear supermarket shelves of the few but dangerous products that say they are ‘gluten free’ but really aren’t due to cross-contamination,” Ratner said.

Many gluten-free companies started following the rules when the FDA approved them. But companies had one year to make needed changes in formulation and handling. Now that the year is up, all food makers who want to use the label have to comply on any food made starting today.

Gluten-Free Living has been writing about gluten-free labeling since the FDA first proposed regulating the label in 2004. The magazine’s editors were among those who testified in early hearings on the labeling changes needed to make food safer for those who have celiac disease, as well as the millions of others who follow the gluten-free diet because of gluten sensitivity.

But there is still a lot of confusion about the rules in the gluten-free community. To help gluten-free consumers understand what to expect, the magazine has put together a free download, “20 Things You Need to Know about Gluten-Free Labels,” available via Facebook, Twitter and at Gluten-Free Living's website.

“A lot of work by many in the gluten-free community, including a grassroots effort, went into pushing the FDA to set these rules,” Ratner said. “It’s paying off for everyone now.”